This invention generally relates to dental devices, and more particularly, to a dental impression tray and bite registration rim assembly which is capable of conveniently taking a precise gum impression and a bite registration in a single visit of a patient.
To prepare a set of dentures for a patient, a dentist needs to take an impression for the patient""s gum as well as a bite registration for the patient""s tooth position and vertical dimension.
Such a procedure usually requires two visits of the patient. In the first visit, the dentist takes a gum impression of the patient by means of an impression tray with an impression material retained therein. For facilitating the maneuver of the impression tray in the patient""s mouth so as to take a precise gum impression, a removable handle may be attached to the bottom of the tray. Andreiko in U.S. Pat. No. 5,752,826 discloses an impression tray with an attachable handle. After the gum impression is taken on the impression material, the impression tray is delivered to a laboratory or factory to prepare a gum mold simulating the shape and contour of the gum. Afterwards, a bite registration rim or block, usually made of a wax, is attached to the gum mold. The gum mold, with the bite registration rim attached thereto, is sent back to the dentist. In the second visit, the bite registration rim, together with the gum mold to which it is attached, is inserted into the mouth of the patient, being adjusted inside the mouth, to take a bite registration.
This two-visit procedure is very inconvenient and costly. Zentz et al. in U.S. Pat. No. 6,196,840 B1 discloses custom a fitting variable dimension bite registration dental impression tray which comprises a bite registration member (wax rim) and a dental impression tray. The gum impression and the bite registration may be taken in a single visit of the patient. In Zenta et al, the bite registration member (wax rim) is fixedly secured to the bottom of the impression tray by melting some of the wax into the holes in the bottom of the tray. The impression tray and the wax rim are always together even in the process of only taking the gum impression. This makes it inconvenient to maneuver inside the patent""s mouth while taking the gum impression and it is also not comfortable to the patient. Furthermore, there is no handle to facilitate the maneuver of the tray and wax rim inside the patient""s mouth. Therefore, it is not easy to use Zentz et al""s invention to take a precise gum impression.
It is an object of the present invention to provide an impression tray and bite registration rim assembly that is capable of conveniently taking a precise gum impression and a bite registration in a single visit of the patient. It is another object of the present invention to provide a method of taking a precise gum impression and bite registration which may be carried out with ease in a single visit of the patient.
According to the invention, a dental impression tray and bite registration rim assembly comprises an impression tray for taking a gum impression, a handle detachably connected to the impression tray by a first connection, and a bite registration rim detachably connected to the impression tray by a second connection. When taking the gum impression, only the handle is attached to the impression tray to facilitate the maneuver of the impression tray inside the mouth of the patient so as to take a precise gum impression. After taking the gum impression, the handle is removed from the impression tray and the bite registration rim is attached to the tray. The impression tray and the bite registration rim, which are now connected together, are inserted into the mouth of the patient to take the bite registration. Only a single visit of the patient is required, and a precise gum impression can be taken conveniently with the help of the handle.
Preferably, the first and the second connections have the same structure such that the bite registration rim and the handle are capable of interchangeably connecting to the impression tray.